In order to measure a blood sugar level of the patient, it is required to take a sample of the blood from the patient with diabetes. At present, various pricking devices have been used to collect a small amount of the blood sample. The pricking device is generally composed of a lancet and an injector wherein the lancet has a pricking component capable of puncturing a predetermined region of the patient's body. The injector has a function of launching the lancet toward a predetermined region. The pricking device is set up for use by loading (or charging) the lancet into the injector. Due to an expansion of the compressed spring of the injector, the lancet is launched toward the predetermined region, and thereby the predetermined region is pricked.
A pricking operation by using the pricking device requires the following nine steps from the loading of the lancet into the injector until the taking out the used lancet from the injector:
(1) Removing an injector cap from the injector;
(2) Setting the lancet into the injector;
(3) Removing a lancet cap from the lancet so as to expose the tip of the pricking component;
(4) Putting the injector cap (which has been removed in step (1)) onto the injector;
(5) Cocking the injector to put the lancet in the loaded state (i.e. make the lancet ready to be launched);
(6) Applying the front end opening of the injector onto a region to be pricked, and then pressing a trigger button to launch the lancet;
(7) Removing the injector cap from the injector;
(8) Putting a protective cap on the exposed tip of the pricking component so as to shield the tip of the pricking component from its surroundings; and
(9) Discharging the lancet from the injector, and then disposing of the used lancet.
Carrying out the above nine steps sequentially is cumbersome and thus it is desired to reduce the number of the steps.
When taking a sample of the blood by using a pricking device, a particular attention must be paid to the handling of the used lancet. In the used lancet, the tip of the pricking component is exposed on the front end of a lancet body, and there may be the patient's blood adhered to the pricking component (particularly the tip of the pricking component) due to the pricking. If the body of a person other than the subject of the blood sampling (for example, a nurse or medical practitioner who collects the blood sample) accidentally should touch the tip of the pricking component, the body of such person may be pricked by the pricking component. This will result in a wound of the body through which the patient's blood may enter the body (i.e. the body of the nurse or medical practitioner), and thus posing a risk of the infection disease.
The presently-used pricking devices are not necessarily designed with due consideration with respect to the handling of the used lancet. It has been proposed to cover the exposed tip of the pricking component with a protective cap after the pricking component is used (see U.S. Pat. No. 5,385,571). However, the covering the tip of the pricking component with the protective cap will in itself carry risk. That is, the lancet with the exposed tip of the pricking component has to be handled when the protective cap is placed thereon. Therefore the risk as described above is still not eliminated.
As will be understood from the above, the pricking device requires utmost attention in handling the used lancet. Due to this, there is a demand for a pricking device that allows it to be disposed of in safety after use (i.e. after the pricking operation).
When the blood sampling is carried out, the pricking component serves to make contact with the body. From this point of view, a sterilization assurance of the pricking component (namely, hygienic soundness of the lancet) is crucial. Thus it is preferable that a lancet holder for housing the lancet has as less area of the opening as possible.
There is also a demand for a lancet capable of controlling the depth of pricking precisely. Particularly such a pricking device is desired that allows it to achieve a constant depth of the pricking, irrespective of the force required for applying the device onto the body.